Table of contents
- 0. Functions7h 52m
- Introduction to Functions16m
- Piecewise Functions10m
- Properties of Functions9m
- Common Functions1h 8m
- Transformations5m
- Combining Functions27m
- Exponent rules32m
- Exponential Functions28m
- Logarithmic Functions24m
- Properties of Logarithms34m
- Exponential & Logarithmic Equations35m
- Introduction to Trigonometric Functions38m
- Graphs of Trigonometric Functions44m
- Trigonometric Identities47m
- Inverse Trigonometric Functions48m
- 1. Limits and Continuity2h 2m
- 2. Intro to Derivatives1h 33m
- 3. Techniques of Differentiation3h 18m
- 4. Applications of Derivatives2h 38m
- 5. Graphical Applications of Derivatives6h 2m
- 6. Derivatives of Inverse, Exponential, & Logarithmic Functions2h 37m
- 7. Antiderivatives & Indefinite Integrals1h 26m
- 8. Definite Integrals4h 44m
- 9. Graphical Applications of Integrals2h 27m
- 10. Physics Applications of Integrals 2h 22m
4. Applications of Derivatives
Differentials
Problem 10b
Textbook Question
Evaluate lim_x→2 (x³ - 3x² + 2) / (x-2) using l’Hôpital’s Rule and then check your work by evaluating the limit using an appropriate Chapter 2 method.

1
First, identify that the limit lim_x→2 (x³ - 3x² + 2) / (x-2) is an indeterminate form of type 0/0, which is suitable for l'Hôpital's Rule.
Apply l'Hôpital's Rule, which states that if lim_x→c f(x)/g(x) is of the form 0/0 or ∞/∞, then lim_x→c f(x)/g(x) = lim_x→c f'(x)/g'(x), provided the limit on the right exists.
Differentiate the numerator f(x) = x³ - 3x² + 2 to get f'(x) = 3x² - 6x.
Differentiate the denominator g(x) = x - 2 to get g'(x) = 1.
Evaluate the limit lim_x→2 (3x² - 6x) / 1, which simplifies to lim_x→2 (3x² - 6x). Now, check your work by factoring the original expression: (x³ - 3x² + 2) = (x-2)(x² - x - 1) and cancel the (x-2) terms, then evaluate lim_x→2 (x² - x - 1).

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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
L'Hôpital's Rule
L'Hôpital's Rule is a method for evaluating limits of indeterminate forms, such as 0/0 or ∞/∞. It states that if the limit of f(x)/g(x) results in an indeterminate form as x approaches a value, then the limit can be found by taking the derivative of the numerator and the derivative of the denominator separately, and then re-evaluating the limit.
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Polynomial Functions
Polynomial functions are expressions that involve variables raised to whole number powers, combined using addition, subtraction, and multiplication. In the given limit, the expression x³ - 3x² + 2 is a polynomial, and understanding its behavior as x approaches a specific value is crucial for limit evaluation, especially when factoring or simplifying the expression.
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Limit Evaluation Techniques
Limit evaluation techniques include various methods for finding the limit of a function as it approaches a certain point. These methods can involve direct substitution, factoring, rationalizing, or using L'Hôpital's Rule. In this case, after applying L'Hôpital's Rule, one can also check the limit by substituting the value directly into the simplified expression or by using polynomial long division.
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